In the prior art, heat insulated tanks utilizing the vacuum heat insulation method are excellent in refrigerating capacity or heat retaining property and widely used for the purpose of storing, for instance, liquid oxygen, liquid nitrogen or liquefied natural gas or the like. However, there are many points to be improved. For example, heat insulated tanks of this kind are constructed with thick inner and outer tanks bearable against a vacuum load, and it is well known that the weight of heat insulated tanks becomes large and some supporting means for the inner tank is indispensable, so that the heat insulating effect is lowered. And, in reference to said vacuum load, the shape of heat insulated tank cannot but be made as a sphere or cylinder with curved ends. These shapes are disadvantageous in view of filling amount or storing capacity. Further, in a heat insulated tank for storing solid goods such as cold or refrigerated foodstuffs to be stored or conveyed, its economical value is very poor, so that in general, a heat insulated tank is used having inner and outer tanks and between which heat insulating material such as polyurethane foam is filled. Thus the heat insulated tank with vacuum heat insulation has not been practically used.